Geophysical surveys are often used for oil and gas exploration in geophysical formations, which may be located below marine environments. Various types of signal sources and geophysical sensors may be used in different types of geophysical surveys. Seismic geophysical surveys, for example, are based on the use of seismic waves. Electromagnetic geophysical surveys, as another example, are based on the use of electromagnetic waves. In some surveys, a survey vessel may tow one or more sources (e.g., air guns, marine vibrators, electromagnetic sources, etc.) and one or more streamers along which a number of sensors (e.g., hydrophones and/or geophones and/or electromagnetic sensors) are located.
During the course of a geophysical survey, the various sensors may collect data indicative of geological structures, which may be analyzed, e.g., to determine the possible locations of hydrocarbon deposits. However, the data may be contaminated by various sources of noise that may complicate the data analysis. In some cases, the expected noise may be modeled and applied to the data as part of a noise-reduction process. Because the noise model may be imperfect, it may be adapted before being applied to the data, e.g., to better fit the general noise model to the particular circumstances in which the survey occurred.
Various challenges may arise in choosing how to adapt a noise model in order to achieve an effective level of noise reduction. Embodiments of this disclosure may be used to address some of these challenges, as discussed below.